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Monday, 7 November 2011

Save Money in Your Garden: Refresh Potting Mix!

You can really only use potting mix once, because whatever you planted will have sucked up all the nutrients BUT you can refresh your potting mix and use it at least once more! If you grow things in pots you will probably have noticed how very different used potting mix looks to new. You can quite easily bring your potting mix "back to life" much more cheaply than buying all new. Potting mix doesn't sound expensive, you can get it for under $4 for 30 litres, but do consider this: 40 llitre tub (the average size for a "big pot") takes more than one bag, and you will certainly need more than one tub. The tubs will need topping up and refreshing regularly. If your garden is in tubs and pots you can't just use dirt out your garden, as this is usually much too dense. To refresh your potting mix and use it again:

You can still reuse the potting mix if the pot has gotten full of weeds; plant one or two sunflower seeds in each pot. When the sunflowers are fully grown, all the weeds will be gone. Sunflowers kill all other plants in their soil and "suck up" the nutrients, and you get beautiful flowers with useful seeds. Hint: sunflower seeds sold as birdseed are cheaper than those sold to be planted, and are just as easy to grow.

This pot was so alive with weeds you couldn't see the dirt. I had a picture to show you but it seems to have vanished, so you'll have to trust me when I tell you this sunflower really did its job!

After the sunflowers have died off (the roots from the sunflowers contain the nutrients from the weeds, but no weed seeds, so don't try to remove them), tip the potting mix into a large tub. If you have a compost heap, add some ready compost, about 1/3 as much compost as you have used potting mix. I used a children's wheelie bin to mix mine.

Add some multi-purpose fertiliser to the tub, several good handfuls; one with a soil wetter included is best, as new potting mix has this included.

I used this one this time, but any product like this would do the same job. The word "complete" is always good. A small bag should be fine as it's usually quite strong.

Mix all of this up together, and it should start to resemble newly bought potting mix a little better.

Here's my mixing job. A good watering and let it sit.

Water the potting mix and let it sit, uncovered or covered with mesh for about a week.

After a week, it looks much more like new potting mix. I watered this right after mixing, and again after three days.

Your refreshed potting mix should now be ready to use. I usually find, since the tub should have no drainage holes, the mix will be a little sticky at the bottom, and may smell a little "organic", but this is fine to use, and is actually full of nutrients.

Of course if you have your own compost heap, you can always use that in your pots, but it takes time to get ready compost, and this is a good alternative while you are waiting. It is best to only refresh your potting mix once, as after this it will become too nutrient rich and may burn your plants, as the "soil" part will be diminished but you add more fertilizer.